This invention relates to a hinge assembly for pivotably connecting a device main body and a cover together, such as a telephone main body of a cellular telephone and its cover, a main body of a toilet and its seat, and the like.
Conventional hinge assemblies of this type include a hinge shaft and one pair of plate springs (resilient members). The hinge shaft is pivotably connected to a device main body and nonpivotably connected to an opening and closing cover. On the other hand, the plate spring is nonpivotably mounted on the device main body and pinchingly holds a cam portion (pivotal movement restricting portion) of the hinge shaft between the one pair of plate springs. By this, the hinge shaft is restricted in its pivotal position and thus the cover is restricted in its pivotal position (see Japanese Patent No. 2,766,074 and Japanese Patent No. 2,906, 346).
In the above conventional hinge assemblies, in order to prevent the cam portion of the hinge shaft from being worn out quickly by being rubbed with the resilient members, a lubricant oil such as a grease is applied to an outer peripheral surface of the cam portion. However, the lubricant oil applied to the cam portion is gradually removed by the resilient members. Consequently, oil short occurs thus resulting in fear that the cam portion is worn out quickly.
According to the present invention, there is provided a hinge assembly having a device main body and an opening and closing member pivotably connected to the device main body, the hinge assembly comprising a hinge shaft disposed on a pivot axis of the opening and closing member, the hinge shaft being pivotably connected to selected one of the device main body and the opening and closing member and nonpivotably connected to the other; and a resilient member nonpivotably connected to the selected one of the device main body and the opening and closing member to which the hinge shaft is pivotably connected; the hinge shaft being formed with a plurality of shaft portions extending generally parallel to the pivot axis, the shaft portions, which are in contact with the resilient member, restricting a pivoting position of the hinge shaft, the plurality of shaft portions being arranged away from one another so that a space is formed between the adjacent shaft portions.
Two or more of the shaft portions may be provided.
In the case where two or more of the shaft portions are provided, an outside diameter of the two shaft portions is preferably small in a mutually opposing direction and large in a direction perpendicular thereto.
It is preferred that the two shaft portions of the hinge shaft are connected to at least that portion of the hinge shaft which is connected to the other (i.e., the device main body or the opening and closing member) such that the two shaft portions are pivotable within a predetermined range about the pivot axis.
It is also preferred that two of the resilient members are provided such that the two resilient members pinchingly hold the two shaft portions from opposite sides thereof.
In the case where three of the shaft portions are provided, they are preferably located at vertices of a triangle.
It is preferred that two of the resilient members are provided such that the two resilient members pinchingly hold at least two shaft portions from the outside of the three shaft portions.